No matter how beautiful the children, each family line carries its own unique panoply of genetic curses. Some families have noses, some have feet, some have ears, others baldness, a waddle, bad breath, rabbit teeth. In my bloodline we have cheeks--enormous, fleshy wads only a grandmother could love, and then, only on a child under five. On the beach with my sisters as kids, we didn't plump our biceps or flatten our stomachs for the snapshots, we sucked in our cheeks and bit down. Yes, we could have just smiled like normal children but then there would have been the endless questions about who'd stuffed all the cherries into our mouths. I'm sure if I looked far enough back in our family history, I'd learn of a particularly harsh famine that had wiped out all but the largest cheeked of us who just barely survived by virtue of the redundant energy stores we held in our faces.

On a balmy May morning, I finished up my run as I had done for the past four months, having taken my cheeks along with me for the entire two miles. I was still in the old sweats I'd started with in February. I made a mental note to pick up a pair of running shorts as I stepped out of my shoes and untied the jacket from my waist and let it drop. Still huffng from the run, I pulled oft my shirt and wiped it across my face and shot it at the hamper and ran upstairs to wash up.

There in the shower I was shaving away, not paying much attention as I drew the razor down the vast real estate of my right cheek, when something really strange happened. The blade suddenly stopped working. I drew it down two more times without effect before realizing what was going on. Where the middle of my cheek had once ballooned to meet the razor, there was only a hollow. In order to finish the shave, I had to do something incredible. I had to make my cheek bigger--the rough equivalent of Yao Ming having to reach higher. I had to puff it out--something possibly no shaver in my family going all the way back to the famine has ever had to do. I put the razor aside and wiped the fog from the shower mirror and turned to one side and leaned in close to find that the cherry-stuffng kid I had tried to ditch my whole life was fading. There, running down the side of my face was the undeniable beginning of a runner's cheek--that sun-cracked, athletic hollow bracketed by smile lines and crow's feet. I could have as easily sprouted wings.

When the task is hard and the progress is slow, you celebrate the small things. When the task is nearly impossible and the progress is glacial, there are no small things and you celebrate all the time--if you want to keep going, you high-five anything and everything that you can remotely trace back to your efforts.

The following week our family joined up with another at an amusement park. Usually by three o'clock in amusement parks, I experience a mood swing as severe as it is predictable, regardless of how many happy corn dogs you throw at me. The morning's promise is hopelessly lost to the frantic, line-to- line scramble of the last six hours. I'm carrying all the backpacks my kids insisted on bringing and promised to carry themselves. The sun angles under the brim of my cap, my feet start to numb, my legs begin to fill with sand, there is a ride on the other end of the park and it's only a mile away and I'll only have to carry my youngest and he's only 50 pounds. I'm not just tired anymore, I'm amusement-park tired, the most hollow and most bitter of any other kind of tired.

That afternoon in the park, the old familiar enemy never came. I was bounding along like a glad-footed, oversized child (as my wife, Susan, describes it), pushing the other family's youngest in his stroller, when Susan ran up to tell me to slow down. I looked back and told her I had no idea I was going so fast and had gotten so far ahead. "I don't know why I'm not tired," I said. Having spent years as a runner, she was quick to diagnose the problem. "You're running now," she said. "You're not going to get tired." I thought about it and only realized then that tiredness was something I hadn't recently experienced. Outside of running itself, I couldn't remember the last time I felt drained or even weary. We returned to the group and I apologized for racing ahead. "Marc would love to walk like a normal person," Susan said, deadpan. "If only he could."

Repeat to self: No small things. Celebrate all the time.

Can you call yourself a man if you have a pair of "skinny jeans" tucked away in the attic? No? Okay, then, there's this guy I know who has been running for four months--he has a pair. He hasn't lost any weight since he started running. He's actually gained a little. His doctor tells him to throw out the scale and keep running under the theory that the guy was putting on weight as he put on muscle. The guy thinks, Hey, let me try on these jeans I used to wear in college. He wonders if he's shape-shifted enough to fit back into them. He goes up to the attic when his family is out of the house and tries them on and takes the fact that he can close the zipper as a small victory. He celebrates and thinks a month from now he might even be able to wear them. This guy I know.

Running changes you. Running is changing me. It knocks points off my blood pressure, returns the color to my face, takes the bags from beneath my eyes. Running makes the brownie taste better. I have no idea why--I eat the brownie and drink the milk and don't ask questions. But the biggest change I've felt a# er four months of running is something I can't see or precisely measure or fully describe, yet it's the change I feel most acutely: I've gone from a person who sits still to one who moves--from a body and a mind at rest, to a body and mind in motion. If you'll excuse the amateur Zen moment.

The only thing running hasn't changed is running itself. I would have guessed that by now it would be easier for me to do. It isn't. People say the run gets easier, but people say aliens abduct you in the desert, too. I've stopped looking for signs of an easier run in exchange for signs of an easier life. Those signs I've seen. Running is still as grueling as ever, but life outside of running is getting easier, better. In the vein of the classic huckster's call, it truly is the One Authentic Tonic for Whatever Ails You! The Only Certified Elixir of Beauty and Health! The A-1 Tincture to Boost Vitality and Strength! If only someone could hand it to me in a small brown bottle. Just my luck that the ultimate supertonic is carried on the wind. I can't see it, but it's there, floating outside the window right now. All I have to do to get a dose is put on my shiny pair of gold and silver Asics and run for it.